Auger downforce unit for use on tractor 3-point hitch mounted earth augers

ABSTRACT

We have invented a way to create mechanical downforce for using post hole augers or other implements on tractor 3-point hitches. Our invention allows the user to switch the post hole auger from conventional mode to downforce mode by removing one hitch pin and inserting two others. Our invention makes it possible to create downforce sufficient for digging in hard, rocky or frozen soils without resorting to unsafe methods. The invention creates a secondary pivot point and a variable attachment point, resulting in the lifting force of the tractor&#39;s hitch being reversed into usable downforce at the auger bit. The invention permits the user of a tractor-driven earth auger to generate mechanical downforce at the auger, without the use of additional hydraulics for easier digging in hard or rocky soils.

The invention consists of one support beam “Lower Mount” (FIG. 1 and FIG. 2, “lower mount”), which attaches to the tractor's pulling hitch receiver or draw bar and provides a lower mounting point. The Lower Mount consists of a steel tube section designed to fit over and capture the tractor's existing draw bar, with a vertically oriented hole such that a mounting pin can be inserted through both the Lower Mount and the draw bar (FIG. 2, “hole for pin to Draw Bar”).

Said mount is further designed with mounting tabs oriented such that a second portion of Lower Mount can be affixed via a horizontally oriented pin and clip, permitting thusly the distal portion of the Lower Mount to have some range of adjustability through an arc about said horizontal pin. Distal end of said Lower Mount further incorporates mounting tabs in a vertical orientation, with horizontally oriented holes, such that the Vertical Bars can be affixed to the distal portion and mounting tabs of said Lower Mount (FIG. 2, “Holes for Pins for Vertical Bars”). Vertical Bars are thereby affixed to Lower Mount such that they can pivot in a forward/rearward direction about a substantially horizontal axis, through an arc proscribed by said pivot pin.

Lower Mount distal end is also supported/reinforced by two diagonal support bars, (FIGS. 1,2,3 “Diagonal Support Bars”) which in some embodiments may be length-adjustable to fit different tractors, with said bars extending from attachment points on said lower mount (FIG. 2, “Holes for Diagonal Bars”) upward and diagonally forward to the fixed central “Upper Mount” attached to the tractor's three-point hitch where the adjustable link would normally be mounted.

The invention additionally has an upper mount assembly (FIGS. 1,2,3 “Upper Mount”) which attaches to the tractor's fixed central three-point mount, with said assembly being fabricated of a multitude of steel plates perpendicular to one another and having a multitude of holes for the attachment of said upper mount to tractor (FIG. 2, “Upper Mount, Mounting holes”) and also for said diagonal support bars (FIG. 2, “Holes for Diagonal Support Bars”) as well as attachments of conventional implements. This allows the user to leave the assembly on the tractor when using other implements instead of the post hole auger. Said assembly has a slot cut in each half of assembly (FIG. 3, “Curved Slot in Upper Mount . . . .”) which serves to capture the proximal mounting point of a conventional earth auger. Said slots are parallel to each other on pair of said upper mount plates, and may be oriented in a substantially vertical plane or inclined such that the upper end of said slots are more rearward than lower end of said slot. In addition, said slots may not be completely straight, with some embodiments having said slot cut in an arc with a constant or variable radius. Inclination and/or curvature of said slots shall be to facilitate the auger bit traveling in a substantially vertical line as auger boom passes through an arc of movement.

Said Upper Mount assembly has holes immediately below said slot, (FIG. 2, “Holes for Anchor Pin”) and two plates (FIG. 2,3 “Anchor Plates), each with a pair of corresponding holes, such that said proximal end of auger can either be pinned in the lower end of said slot, or unpinned and permitted to slide upward or downward in said slot (FIG. 3, “Two Modes of Auger Usage”). When the proximal end of the auger boom is captured and pinned at the bottom of the slot, auger functions in “conventional mode” (FIG. 3, “Conventional Mode”), with the tractor's 3-point hitch lifting causing an equal amount of lifting of the auger. This mode is used either for transport, or for extracting the auger bit from the hole once it has been dug down to a sufficient depth.

When the proximal end of said auger boom is unpinned from said holes at the bottom of said slot in upper mount, auger boom is free to move through the length of said slots in upper mount, and downforce mode is engaged such that lifting with the tractor's hitch causes downward force on the auger (FIG. 3, “Downforce Mode”).

The invention has two vertically oriented arms named “vertical bars” (FIGS. 1,2 “Vertical Bars”, made of square tube steel in the most common embodiment, which are attached via pivoting pins at the end of said Lower Mount support beam (FIG. 2, Lower Mount, “Holes for Pins for Vertical Bars”). Said bars extend vertically such that they pass on either side of the approximate mid-point of the boom arm of the earth auger. At said mid-point, there are two larger square tubes, “outer sliders” (FIG. 1,2, “Outer Sliders”) of much shorter length, sized such that they can slide over said vertical bars. Said “outer sliders” each have a steel tab protruding in the vertical plane and parallel to the medial surface of said outer slider tube, with said tab having a hole about a horizontal axis (FIG. 2,Outer Slider, “Holes to Bolt to Auger Boom”). Said holes in each respective tab on said outer sliders serve to provide an attachment point and therefore a secondary pivot point to attach to the auger's main boom. Said Outer Sliders additionally have a secondary tab oriented at 90 degrees to the “Holes to Bolt to Auger Boom”, with holes permitting pinning to the Vertical Bars (FIG. 2, “Holes to Pin to Vertical Bars”).

The vertical bar tubes have a multitude of holes drilled at regular intervals, (FIG. 2 Vertical Bars, “Holes to Pin to Outer Sliders”), which correspond to a hole in each of the shorter outer tubes. Said inner/outer tubes can therefore, through the use of a common hitch pin, be secured such that the short outer tubes are affixed to the long vertical arms, and the bolt through the two tabs on said outer slider tubes passes through a corresponding tab and hole in the auger main boom (FIG. 1, “Secondary Pivot”, FIG. 3, Downforce Mode, “Pivot”), at approximately the halfway point along the length of said main boom (see FIG. 1, “Vertical Bars, Outer Sliders”) When the vertical bars and outer sliders are pinned together, and the proximal end of the main boom is unpinned, the main boom can pivot about a horizontal axis at approximately its mid-point (FIG. 3, “Downforce Mode”).

The concept that is used for digging in the downforce mode is that instead of the lifting arms being attached between the pivot and the auger bit, the pivot point is moved so that it lies between the lifting arms and the auger bit. Because the pivot is situated thusly, and the proximal end of the boom free to travel through the slots in the Upper Mount, the lifting action of the tractor's arms is converted to downward force at the auger bit through a pivoting action about an axis formed by the bolt joining the outer slider tubes and the midpoint of the auger main boom (FIG. 3, “Downforce Mode”).

The downforce mode is engaged when, during the course of digging a post hole, the user encounters some rocks or hard soil, and wants to be able to penetrate through that layer. The user stops the PTO on the tractor, and unpins the proximal end of the auger, so that it is free to slide up and down in the long slot provided in the Upper Mount assembly which is bolted to the mount on the tractor. Then, the user places two pins in the vertical bars and outer sliders, pinning them together and forming the secondary pivot point for the boom arm of the auger. These two actions are all that is required to engage downforce mode for digging. At this point, the user can re-engage the tractor's PTO shaft drive, and upon using the tractor's lift control lever to lift the tractor's hitch, the auger will be forced downward into the soil.

When the hole is completed to the required depth, the user can lower the tractor's lifting arms, which will allow the proximal end of the boom arm to reach its lowest point in the upper mount slot. The user then pins the boom in the lowest position, and unpins the vertical bars from the outer slider tubes. At this point, the auger can be lifted out of the hole in the conventional manner (FIG. 3, “Conventional Mode”) by using the tractor's lifting force to lift the boom and auger upward.

Potential alternative embodiments or options include using a ratchet mechanism on each vertical bar instead of holes and corresponding pins on the inner and outer tubes (This would allow for digging the entire hole in downforce mode by alternately lifting and lowering the 3-point lift). Ratchet mechanisms would be oriented such that the outer sliders are kept from sliding upward on the vertical bars, but are free to slide downward on the said vertical bars.

Additionally, an alternative embodiment may involve using spring mounted pins with wedge-cut ends, such that said pins will engage automatically in one direction and can be disengaged via cable pull and lever from the tractor operator's seat.

Optional additions which would enhance the combination of our invention and the current art auger mechanism would be the addition of a slipper clutch at the end of the PTO shaft to reduce shock loading to the gearbox on the auger, and also potentially using a carbide-tipped rock auger bit. These bits are more expensive, and designed for drilling fracturable or even solid rock. They typically are not used on conventional augers due to the lack of sufficient downforce to actuate the cutting teeth in hard materials; with our invention a rock auger bit could be used on a farm tractor/auger. Both the aforementioned slipper clutch and rock auger bit are prior art and easily available as optional upgrades to add to the earth auger/downforce unit combination.

DESCRIPTION OF ILLUSTRATIONS

FIG. 1:

This illustrates the Auger Downforce Unit installed on a tractor with the Auger. The purpose of this illustration is to show the relative position of components when installed.

FIG. 2:

This illustration shows the individual components that comprise the Invention itself, the Auger Downforce Unit.

FIG. 3:

This illustration is a detail view of the Upper Mount attached to the Tractor, with the Auger Boom installed.

FIG. 4:

This illustration demonstrates the concept behind how the Auger Downforce Unit operates, by showing both operational modes:

4 a: “conventional mode” where the Tractor's lift will raise the Auger bit.

4 b: “downforce mode” where the Tractor's lift will push down on the Auger bit. 

1. We claim a new device to create downforce for a tractor-mounted post hole auger or other farm implement, with said downforce unit being comprised of several components: a) an Upper Mount which captures the proximal end of the auger boom and includes an angled, straight or curved slot which defines the travel path of said proximal end of auger boom. Said angulation or curvature of said slot serves to compensate the the distal portion of the Auger Boom traveling through an arc, and changes that arc travel to a substantially vertical plane of travel such that holes are more easily created vertically in the ground. Said Upper Mount includes a multitude of mounting holes to permit affixing of other farm implements when the Auger is removed. Said Upper Mount further includes holes below said slots, for the purpose of anchoring the proximal portion of Auger Boom in the lowermost position of said slots, for use in Conventional Mode, without downforce. Said Upper Mount further includes holes for the mounting of diagonal support bars to support the distal portion of the Lower mount. b) a Lower Mount which extends rearward from the tractor's pulling hitch. Said Lower Mount's purpose is to provide a stable lower anchor pivot point for the Vertical Bars which comprise the Downforce Pivot Point. Said Lower mount is further supported by two diagonal support bars connecting the rearward, distal point of the Lower Mount with the lateral aspects of the Upper Mount which is bolted to the tractor. c) Vertical Bars which extent vertically from the distal end of the Lower Mount, with a multitude of holes or notches, for purpose of anchoring/indexing with Outer Slider tubes. d) Outer Sliders, which slide longitudinally over said Vertical Bars and have a set of corresponding holes such that pins can be inserted through Outer Sliders and Vertical Bars anchoring them together. Alternatively Outer Sliders can incorporate spring loaded pins or teeth which index in notches in the Vertical Bars, in a ratcheting method. Said Outer Sliders bolt together on either side of a mounting tab on the superior aspect of the Auger Boom, at a point proximate to halfway along its length. Said bolted union of Outer Sliders and Auger Boom comprises the Downforce Pivot Point which allows the generation of downforce when the proximal end of the Boom is unpinned from the anchor holes in said Upper Mount and permitted to travel vertically. e) optional addition of a two-piece clamshell type assembly which surrounds and captures the auger boom and provides an attachment point for the secondary pivot. This is only necessary when using the downforce unit with an auger boom which does not have a suitable hole for a secondary pivot point.
 2. We claim a method of mechanically creating downward force for tractor-mounted implements, through the creation of a secondary pivot point of variable height, located away from the tractor and the creation of a variable-height proximal attachment point at the rear of the tractor. This secondary pivot point makes it possible for the lifting action of the tractor's 3-point hitch to be translated into downward force on the opposite end of the secondary pivot point, greatly facilitating the use of implements such as post hole augers as well as making said augers safer to use and easier to control. 